Abstract: In this research, esterified Rice Bran Oil (RBO) and non-esterified RBO was investigated for its performance as a compression ignition engine fuel. In this context experiments were conducted on single cylinder water cooled diesel engine with diesel, RBO, preheated RBO and Bio-diesel (esterified RBO). Performance parameters like thermal efficiency, specific fuel consumption and emissions such as smoke, particulate mater, unburned hydrocarbon, carbon monoxide and oxides of nitrogen have been measured. The performance of the engine with diesel has been used as the basis for comparison.